Fuse



5 Sheets-Sheet l J. P. ARNDT FUSE Filed March 2l 1919 Sept. 23. 1924.

J. P. ARNDT- Sept. 23, i924.

FUSE

Filed March 21. 1919 5 Sheets-Sheet 2 EIL/v.

sept. 23, 924. v 1,509,185

J.`P. ARNDT 4 FUS E Filed March 21. 1919 5 Sheets-Sheet 3 J. P. ARNDTSept. 23, yl924.

1919 5 Sheets-Sheet 5 Filed March 21,

Patented Sept. 23,` 1924.

UNITED STATES I JOHN P. .ARNDT, OF SOUTH MILWAUKEE,

g 1,509,185 TENT! oFFicE.

WISCONSIN, ASSIGNOR TO LINE MATERIAL COMPANY, O'F SOUTH MILWAUKEE,WISCONSIN, CORPORATION 0F WISGNSIN.

FUSE.

Application med Haren 21, 1919. serial No. 284,059.

To all whomy t may conce/m:

Be it known that I, JOHN P. AnND'r, a citizen of the United States,residin at South Milwaukee, in the county of 'lwaukee and State ofWisconsin, have invented new and useful Improvements in Fuses, of whichthe following is a specifica-l Another object is to provide acomparatively shortl fuse capable of effectively interrupting highvoltage heavy current circuits. Another object is to provide a fusewherein the circuit is positively broken when the fuse-link is ruptured.

Another object is to provide a fuse which effectively prevents thereformation of any arc between its terminals. n

. Another object is to provide a fuse where- `in the danger of an arc'destroying the fuse cartridge is reduced.

Another object is to provide an enclosed fuse wherein the fuse-link maybe readily replaced. p

Another object is to provide an improved interchangeable fuse so thatrepairs need not; be made where the fuse is located, or

` Service interrupted until repairs are com- Another object is toprovide a fuse wherein thev fuse-link may be replaced and repairs may bemade with minimum danger.

Another object is to provide an improved fuse which gives an indicationupon being blown.

-Another object is to provide an enclosed fuse whereinthe gasesgenerated when the fuse-link is ,volatilized are readily allowed toescape.

Another object is to provide a fuse which is vented outside of itsenclosing casing.

Another object is to provide a fuseof' the enclosed type which isreliable in operation, easily applied, and readily manufactured.

Other objects will appear from"the following specification and claims.

Several embodiments of the invention are illustrated in the accompanyingdrawings in which Figure 1 is 4a front elevation of a fuse in aprotecting casing whose door, which is removed, forms the fuse mounting;

Fig. 2 is a partial sectional elevation thereof, the door of the casingbeing shown in both open and closed positions;

Fig. 3 is an enlarged longitudinal section of the fuse cartridge, theparts being shown in normal position;

Fig. 4 is an enlarged longitudinal section of aportion of the cartridge,showing the position the parts assume when the fuse is blown.;

B Fig. 5 is a cross section on the line 5 5 of Fig. 6 is a frontelevation of a fuse `mounted openly;

Fig. `7 is a side elevation thereof;

Figs. 8 and 9 are longitudinal sections of a modified construction;

FFig. 10` is a section on line 410-10 of `ig. 11 is a section Fig. 9; Y

Fig.. 12 is a perspective of the lower switch;

Fig. 13 is a longitudinal sectional view of another modied construction;

Fig. 14 is an end view thereof, and

Fig. 15 is a cross section on the line 15-15 .0f Fig. 13.

Figs 1 to 5, inclusive, will first be described.

The fuse cartridge comprises, in general, a tube 1 enclosing a fuse-linkand provided with terininals 2 and 3 between which the link extends. Thetube is rigidly secured to the back of a porcelain door 4 ofan-enclosing metallic housing 5. .terminals 2 and 3 is provided with a'swltch blade G adapted to be pressed and held between correspondingswitch clips 7 when the door is closed. Clips 7 are supported from theback of the casing on suitable insulators 8," and to these clips theline conductors are secured. The line conductors enter casing 5 throughinsulators set in suitablepockets in the casing.o When the casing dooris closed the circuit is completed from one line conductor through theupper switch, terminal 2, the fuse-link, terminal 3 and the lowerswitchto the other line conductor. circuit is broken. f l

Tube 1 is made of a! suitable insulating on the line 11-11 of materialsuch as fiber. By means of a metal.

Each of the When the door is opened' the strap 9 it fis secured, nearits top, to a support interconnecting the door strengthening ribs 10.The lower end of the tube is cari ried by a collar 11 which is alsosecured to the door. *Projecting laterally from collar 11 are va pair oftrunnions 12. These trunv; nions rest in open topped bearings 13 formedin projections 14 which lextend inwardly from oppositev sides of thecasing. The

door pivots upon trunnions 12 and may be readily removed by4 raising thetrunnions from the bearings.4 'A handle 15 is provided for the door tofacilitate the opening or removal thereof. TheI open condition or' thedoor is limited by a stop 16 which is carried by a pair of arms 17extending downwardly from collar 11, engaging the bottom 18 of thecasing. The engagement of the stop and bottom of the casing alsoprevents the door from drop ing out of its bearings.

The door! andpcasing have been described as being res ectively composedof porcelain and metal.

owever, beth may be made of metal or both of porcelain, or either orboth may be made of wood or other material suitable to-rthe, conditionsof operation, service and location. A

vReferring' especially to Figs. 3 and 4 the construction of the fusecartridge will be .more particuarly described.

The upper terminal 2 forms a cap or clo sure for theupper end 'of theouter tube- 1 into an annular groove 25 where it is securely clamped inposition by the annular projection 26 on nut 21 when the nut Ais 'turnedhome. The interlocking ofthe groove 1n the terminal and the projectionon' theclamping nut form a tight joint to prevent the escape of gas orthe passage of an arc.

-The upper end of the inner wall of the` ter?.

minal is tapered to facilitate the placing of the fuse-link.- The lowerterminal '3 has a screw 27 and a nut 28 for securing thereto the lowerend of the fuse-link. The terminal and nut are respectively providedwith an i annular .groove and an annular projection which interlock toprevent the escape of gas through aligned openings in the tubes. The

link passes through terminal 3 and the outer tube by an opening 29.Terminals 2 and 3 are secured to Vtube 1 by screws 30 or other suitablemeans. V l

Telescopically slidable within tube 1 is an inner tube 31 which isopen'at its upperend. The lower end of the inner tube is closed by arubber plug and cushion 32 held in place by a pin 33. The inner tube isalso c omf posed of a suitable insulating material such as ber. 1 isprovided with a small opening 34 in its side wall which is adapted toalign with opening 29 in the outer tube and terminal 3 to rovide for thepassage of the fuse-link. T ese aligned. openings pass throughthe'wallsfofthe tubes and terminal 3 in a diagonal direction tofacilitate the threading of the fuse-link therethrough. lNear its closedend inner tube 31 is provided with a vent opening 35. This opening ispositioned above the open end of outer tube 1 and closed by the sidewall thereof when Athe inner tube is in its normal or raised positionshown in Fig. The two telescopically arranged tubes thus provide asubstantially7 closed pressure chamber in which ,the fuselink ispositioned. When the fuse is blown the inner tube is forced downward,movin r vthe vent opening. 35 below the lower edge oil the outer tuberallowing the gas within the chamber toesca e. j h

The inner tuge is normally held in elevatedk position by the linkpassing through and engaging the walls of the aligned openings 29 and34. In order to locate and localize the rupture of the link upon thepassage of excess current therethrough, the link is provided with arestricted cross-section.

where it passes through the aligned openings inthe tubes. This may beaccomplished by doublin and twisting a -fuse wire upon,

itself for t e greaterportion of its length,

leavin" it of a single strand where it passes throug 1 the alignedopenings. Thus the weakest portion of the link is at the alignedopenings andthe rupture is localized at this point. The link may be madeof'fuse ribbon instead of wire. If ribbon 'is employed the restrictedportion may be provided by making the cross section less where it passesthrough theopenings. It is not necessary to localize the rupture, but bydoing, s o the operation is particularly satisfactory.

The operation of thecartridge is as follows: When the fuse-link isintact the telescopi'c tubes are in the position shown in Fig. 3. Uponvthe vpassage of excess current through thefuse-link the entire link isheated and the restricted portion thereof begins to volatilize andvfuse. Theheat generated and the gases of volatilization produce apressure within the `chamber which forces the inner tube downward. Thismovement abruptly breaks the alignment `of openings 29 and 34 and cutsnot only whatever of the ing e'ect of cushion 32. The tubes are now linkmay remain intact, but-also any arc in the position shown in Fig. 4andsince the alignment of the openings therein is broken, the walls ofthe tubes present a complete barrier to any reformation or the arc orsparking betwen the terminals or the severed ends of the fuse-link.The'circuit between the terminals is thus effectively broken and also,since no arc persists, the danger of destroying the cartridge isreduced. Since the vent opening is now outside of the enclosing casingthe gases in the chamber can `escape to the .open air. Thus there is nodanger of these gases providing a comparatively low resistance pathbetween the fuse terminals or switch members outside of the tubes. The

ylower end of the inner tube also serves as an indication that the fusehas been blown, as clearly shown in Fig. 4, and the dotted line of Fig.1.

To replace the fuse-link, nut 21 is unscrewed from the upper terminaland the upper terminal is removed from the outer tube. 'Nut-28 is alsounscrewed and the remaining ends of the ruptured link are removed. Theinner tube is. next moved back into the outer tube and openings 29 and34 are aligned. The fuse-link is then inserted through the alignedopenings, which may be made large enough to pass the largest portion ofthe link, and its low'r end is clamped to the lower terminal by nut28.,- The upper end of the new link, which extends above the open endof' the outer tube, is threaded through opening 22 and the upperterminal is replaced and fastened in position.. The upper end of thelink is then passed through transverse groove 24 around the annulargroove 25 and clamped in position by nut 21. Such replacements may bereadily made without danger because the opening of the casing doorrenders the cartridge accessible,

and disconnects the cartridge terminals trein the line. Anotheradvantage of the fuse is that, because the casing doors may be easilyremoved and made interchangeable, the door and cartridge of a blown fusemay be re placed by, another door with an unblown cartridge. Thisadvantage is of special importance in making repairs at night or instormy weather, since, by keeping an extra stock of casing doors andcartridges, the blown fuses may be repaired in the light and under coverat any time, and not necessarily where the 'fuse is located and underadverse conditions. I

Figs. 3 and 7 show a fuse adapted for mounting openly. The cartridge islike that previously described, comprising. the outer tube 1 withinpwhich is telescopically arranged the inner tube and a fuse link. Theupper and lower terminals 2 and 3 are provided with the switch blades 6and respec` tively' withthe fuse-link clamping nuts 2l and 28. Thecollar 11 carries a stop 16 but in this construction does not carry thebearing trunnions. Immediately below terminal 3 is a split collar 36clamped to tube 1 by screws 37. Collar 36 has a pair of downwardlyextending arms 38, the lower ends of lwhich are formed into trunions 39.Trunnions 39 rest in open topped bearings formed in apair of arms 4()which depend from an insulator 41. Insulator 41 is adapted to be mounted-in position in any of the usual ways. insulator 41 also carries theswitch clip 7 with which the lower switch blade (3 cooperates. The upperswitch clip 7 is carried by an insulator 42. rlhe cartridge may Figs. 8to 12 inclusive show a modified Aconstruction wherein ythe cartridge 1senclosed in a porcelain or other insulating body. The outer casing 45comprises a hollow body whose bore is enlarged at thetop and bottom. Theupper enlargement is provided, adjacent its bottom, with threads 46 frwhich may be molded with the body. rlhese threads receive a hollow nut47, which may be of lead or other suitable material, for clamping oneend of the fuse-link as will be hereinafter described.

rlhe cartridge comprises an outer tube 48 of liber or other insulatingmaterial. rTube 48 is open at both ends. Its lower end is threaded toreceive the corresponding threads on the inner wall oit a lrecess in ahandle plug 49. Plug 49 supports the fuse cartridge. A. substantiallyZ-shaped switch blade 5() has one end resting against the bottom. of theplugl recess and its other end overlies theupper end of the plug" whereit is in a position to be inserted between the jaws of and clamped by aswitch clip 51. Blade 50 which forms one fuse terminal is secured toplug 49 by a screw 52. Clip 5l is secured to the under side of the lowerenlargement in tube 45 by a pair of screws 53 and to it .one lineconductor is clamped. The other fuse terminal comprises a sleeve 54secured to tube 48 by a screw 55.' A split metal sleeve 56 having anoutwardly' projecting flange 57 is adapted to fit over sleeve 54. Theother line conductor is coiled about sleeve 56 and is clamped in placebetween the fiange- 57 and nut 47. Nut 47 may be provided with openings58 for the insertion of a suitable tool to facilitate its rotation. Aninsulating washer 59, having l l'O a press fit within the bore of 'body45, but

. a comparatively loose tv with tube 48 so vtu ' ings are in alignment.

that the tube may be moved therethrough, is forced into the bore betweenits upper end and nut 47. l

Telescopicallv arranged within tube 48 is a s lidable inner tube 60which is open at its lower end but closed at its upper end by a plug andcushion 61. The two .tubes 48 and 60 are provided with small openings62.

tube 48, and is clamped in place between plug 66 and lswitch blade 50when tube 48 is screwed home within the recess in plug 49. t

A metal hood 67 covers the upper end of the fuse, being secured to .theporcelain body 45 by inwardly projecting ribs 68. Blevtween the ribs thehood is spaced from the body to allow ready escape of the gases.

The action' of the' gas pressure upon the telescopically slidable tubes48v and 60 when excess current passes through the fuse-link is preciselythe same as that previously descrlbed. The path inside the tubes betweenthe terminals is effectively severed and blocked when the alignment ofthe openings is broken, andl the t gas chamber. is vented. The formationofvan arc between the end of the ruptured link or the lower terminal andthe upper terminal through the vent opening is prevented by theinsulating washer 59. The entire cartridge may be removed for inspectionand replacement of the link by turmng lug 49 until switch lblade 50 isdisengagedv rom clip 51 and then pulling the cartridge 'out of the boreof I body 45. 45'

Figs. 13 to 15 inclusive show, a modified construction particularlyadapted for use with the ordinary spring Vfuse clips.

The cartridge comprises a fiber outer'tube anda telescopically slidableinner fiber' tube .71. v These tubes are provided with openings 72through which a fuse link 7.3

asses when the openings are in alignment.'

he `inner tube 1s open at one end and closed at the other.

One end of the outer tube is threaded to receive the threaded end of ametal ferrule 75. Ferrule 75 forms one terminal of the fuse cartridge.This end of the outer tube is closed by a metal disc 76; Disc 76has a'small o ening 77 for the passage ofthe fuse lin which is clamped betweenthe outer surface of the disc and a screw cap 78. The opposite end ofthe'tube is open, and carries a metal ferrule 79. vFerrule 79 is securedto tube 70 by having one edge means, and is externally threadedthroughout va, portion of its length to receive a threaded metalterminal ca-p 80. One end of the fuse-link is fastened beyond thealigned openings in the tubes' by being clamped between the edge of cap80 and a shoulder 81 on ferrule 79. .Cap 80 is vented by an opening 82.This fuse is readily inserted in spring terminal clips 83 which embracethe metal terminal ferrule 75 and cap 80.. This .fuse also operates inthe manner hereinbefore described, except that the chamber is not ventedby an additional opening in the inner tube. VVhat'ever gases escapebetween the tubes can pass out of minals, said fuse link bein fastenedat one end toone tube and extending into the other tube and producing inthe chamber a gas pressure upon the volatilizatiorr of the fuse Vlinkdue to excess current therethrough to cause relative movement of thetubular'membersl so as to interrupt any circuit between the terminals.

-2. A fuse comprising a pair of telescopically relatively slidable4tubes closed. at their opposite ends to provide a chamber,a pair ofspaced terminal sand a fuse linkv 'extending into the chamber betweemsaid terminals,saidlfu'se link being fastened to the outer tube andextending into the. inner tube, the gas pressure produced by thevolatilization of said link causing said tubes to move relatively toveach other to interrupt any circuit between said'terminals.v

3. A fuse comprising an outer tube having one end closed, an inner tubehaving a closed endand telescopically arranged within' and closing theopen end of the outer tube, a pair of spaced terminals, and a fuse linkextending between said terminals. longitudinally within lsaid tubes andthrough .aligned openings therein, the gas -pressure produced by thevolatilization of said link upon the passage of excess currenttherethrough causing relative movement-of said tubes to interrupt thecircuit between said terminals by-`the breakingl ofthe alignment ofthe oenings. t

4. A se comprising a pairof telescop-` ically slidable tubes forming a'gas chamber,

a pair of terminals, and a fuse-link within said chamber to complete acircuit between said terminals, the pressure of gas within the chamberproduced by the volatilization of 'said link causing relative movementbetween said tubes to irst interrupt any circuit between said terminalsand subsequently to'relieve the pressure of gas within the chamber.

A fuse comprising a pair of telescopically relatively slidable tubesclosed at separated points to provide a chamber, a pair `of spacedterminals, a fuse-link extending into the chamber between said terminalsand producing a gas pressure upon volatilization of the fuse-link duetoexcess current therethrough to cause relative movement between saidtubes to interrupt th'e circuit between said terminals, and means forventing said chamber to allow the escape of the gas therefrom after thecircuit is interrupted.

6. A fuse comprising a pair of telescop.

ically arranged tubes having their opposite ends closed and providedwith aligned openings through their 'side walls, a pair of spacedterminals for the outside tube, and-a fuse-link extending within saidtubes and through the aligned openings, to complete a circuit betweensaid terminals.

7. A fuse comprising a pair of telescopically arranged tubes havingtheir opposite ends closed to form a chamber and provided with alignedopenings through their side walls, a pair of spaced terminals mounted onthe outside tube, and a fuse link extending between said terminals.through the chamber and the aligned openings.

8. A fuse comprising a pair of telescopi- -cally arranged tubes forminga chamber and adapted to slide relatively to each other,

, said tubes being provided with aligned openings, a pair of spacedterminals, and a fuselink extending into the chamber through "saidaligned openings to complete a circuit acting to hold the tubes in sucha 'position that the vent opening is closed by the outside tube when thelink is intact, the gases produced lby' the volatilization of said linkacting to cause. relative movement between said tubes so that thealigned openings are separated and the vent opening is beyond.

the open end of the outer tube.

10. A fuse comprising an outer tube closed at one end and having anopening through the side wall thereof, a pair of spaced terminalstherefor, an inner tube closed at one end and slidable within the outertube and having an opening aligning with the opening in the outer tube,and a fuse-link extending between said terminals and through saidaligned openings.

11. A fuse comprising an outer tube closed at onefend and having anopening through its side wall, a pair of spaced ter- `minals mountedupon`the outside of said outer tube, an'inner tube closedl at one endand slidable within the outer tube and` having au opening aligning withthe opening in the outer tube, and a fuse-link extendingv within saidtubes between said terminals and through the aligned openings.

12. A fuse comprising an outer tube of insulating material closed at oneend and Y having an opening through the side wall thereof, a -pair ofspaced terminals mounted upon the outside of said outer tube, an innertube closed at one end and slidable within said outer tube and having apair of openings one opening aligning with the opening in the side wallof the outer tube and the other opening being closed by the wall of theouter tube before the fuse is blown, and a fuse-link extending betwgeensaid terminals within said tubes and through the aligned openingstherein to complete the circuit between said terminals and normallysupport the inner tube. l

13. A fuse comprising a pair of telescopically arranged tubes, a chamberformed within said tubes, and a fuse-link within said chamber extendingthrough alined openings in the walls of said tubes, the gas pressureproduced by volatilization of said link upon the passage of excess(current therethrough causing relative movement 'of said tubes tointerposea non-conducting wall across the path of said link.

14. A fuse comprising a pair of telescopivcally arranged tubes, each ofwhich is open at one end, a chamber :formed within said tubes, afnd afuse-linkin said chamber, the gas pressure produced by volatilizationet' said link upon the passa e ofexcess current therethrough' causing reative movement of said ltubes to interpose a non-conducting wall acrossthe path of said link.

15. A 'fuse com rising' a pair of telescopically arranged tu and afuse-link therein, the gas pressure produced b volatiliza.- tion of theuse-link'causing re ative movement between said tubes to positivelyintei-,

rupt the circuit and provide an indication thatl the fuse is blown.

16. A :tuse comprising. a fuse-link and a pair of telescopicallyarranged members forming a chamber within which said link is located,the gas Apressure produced in the terminals,

lao

chambers' upon the volatilizatilonJ of said link causing relativemovement between said members to give an-indication that'th@ fuse is'blown. Y

17. A fuse cartridge comprising a pair of a. pair of telesco icallyarranged and relatively movable tu esl coacting to form a gas chamber, afuse-link 'completing a circuit between said termina-ls and extendinginto said chamber, said lnkvolatilizing u n the passage of excessVcurrent thererough, producing a gas pressure within the chamber to causerelative movement between said tubes 'to prevent the formation of an arcbetween said terminals and'vent the chamber.

18. A fuse cartridge comprising apair of telescopically arranged tubesforming a. gas

chamber and provided with aligned open- .ings through their side walls,

and a fuse-link anchored at both ends and extending into' said chamberthrough the aligned openings, said link upon the passage of excesscurrent therethrough creatinga gas pressure within said chamber due tovolatilization of said link whereby said tubes are moved vrelatively toeach other to break the alignment of the openings bo interrupt thecircuit and prevent the formation or maintenance of an arc.

19. A. fuse. comprising an outer tube havingone end closed, an innertubetelescopically. arranged within the outer tube, a pair ofspacedterminals, and -a fuse link extending -between said terminals lonitudinally within said tubes `and through allned openings therein, thevolatilization of said link upon the pas,- sage of excess current.therethrough causing re ative movement of said tubes to interrupt thecircuit between said terminals by breaking the alinement of theopenings.

20. A fuse comprising an outer tube closed at through the .sidewallthereof, a pair of spaced terminals therefor, an inner tube slidablewithin the outer tube and havingI an opening alining with the opening inthe outer tube, and a fuse-link extending between said alined openings.

21. A fuse comprising an outer tube closed at one end and having anopening.

through its side wall, a air of spaced terminals mounted -upon t eoutside of said outer tube, an inner tube slidable within the outer tubeand having an opening alinin with the opening in the outer tube, andv ause-link extending within said tubes between said terminals and throughthe al'inedl openin 22. insulating materia closed at one end and the gaspressure produced by one end and having an opening- Asfuse com rising anouter tube of.

ing a pair of openings, one opening alinouter tube and the other openingbeing closed by the wall of the outer tube before the fuseis blown, andafuse-link extending between said 'terminals within said tubes andthrough the alined openings therein to'complete the circuit between saidterminals and normally support the inner tube. 1.23. 4A fuse comprisinga pair of telescopica-lly slidable tubes,a pair of spaced Vterminalsmounted on the outside of the outer tube, a fuse-link passing throughthe inner tube and having its outer end secured to the terminals, thepressure of gas within the inner tubeproduced by the volatilization ofAsaid link causing the outer end portion of the inner tube to move outof the outer tube a fusible element for releasably holding thereceptacles in telescopedposition and adaptthe fuse is ruptured.

ed to release the interior` receptacle when' fusible element forvconnecting the members of relatively movable tubular tele-v lng withthe opening in the side wall of the y 1s substantially closed at one endand hav- -.ing its other end open to the atmosphere and 25. -Incombination, in an expulsion fuse, ,95

a air of separate terminal members, al

anda casing for enclosing the fusible element adapted to be elongated bythe arc gases nincident to rupture of the fusible ele-v ment forincreasingr the length ofthe path of l the arc between the terminals.

, 26. In combination, in 'an expulsion fuse,

a pair of separate terminalvmembers, a* fusible element for connectingthe members, a

casing for enclosing the fusible element andmeans movable longitudinallyof the casing and actuated by arc gasesmcident. to. the rupture of thefusible element for increasing thellength of the. path of the arcbetween terminals and through said i the said terminals.

The combination with rate fixed 'terminal members, a tubularfcasing anda fusible element for connectin the terminal members disposedlongitudinal y of ythe casing, of a meansL actuated by gases ofvolatilizatio'n of the fusible member and a pair of sepa movablelongitudinally of the casing for in- I creasing the length of the pathof the4 anc between the terminal members.

In witness whereof, I have hereunto subscribed my name.

vJOHN P. ARNDT.

